<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title></title>
    <style>
    html,
    body {
        height: 100%;
    }

    body {
        margin: 0;
        background-repeat: no-repeat;
        background-size: cover;
        background-position: center;
        background-attachment: fixed;
        background-image: url(http://pic1.win4000.com/wallpaper/b/589d687069ed9.jpg);
    }

    /*h1{
        height: 100%;
        width: 100%;
        margin: 0;
        padding: 0;
        color:#fff;
        background-color: rgba(0,0,0,0.5);
        display: -webkit-flex;
        display: -moz-flex;
        display: -ms-flex;
        display: -o-flex;
        display: flex;
        justify-content: center;
        align-items: center;
    }*/
    #big_box{
    	height: 2000px;
    }
    </style>
</head>

<body>
    <h1>按住Ctrl+滚动滚轮：可以看到文字缩放，背景不动</h1>
    <div id="big_box">
    	
    </div>
</body>
<script type="text/javascript">
	function Fun() {
        this.team = "rng"
    }
    let f = Fun()
    console.log(f) // undefined
    console.log(team) // rng
    console.log(f.team);
</script>
</html>